select distinct dose_form_name
from intermediate.int_rxnorm_clinical_products_to_ingredients
where ingredient_name = 'prednisone'
	and ingredient_tty = 'IN'

/* answer = Delayed Release Oral Tablet, 
Oral Capsule, Oral Solution, Oral Tablet, 
Rectal Suppository */

select
    ingredient_component_name
from intermediate.int_rxnorm_clinical_products_to_ingredient_components ing
left join staging.stg_rxnorm__ndcs ndc
	on ing.clinical_product_rxcui = ndc.clinical_product_rxcui
where ndc = '00597014660'

/* answer = linagliptin, metformin */

select
	cls.class_name
	, count(*)
from staging.stg_fda_ndc__ndc ndc
left join staging.stg_fda_ndc__class cls
	on ndc.productid = cls.productid
where to_date(product_startmarketingdate, 'YYYYMMDD') >= current_date - 90
	and cls.class_type = 'EPC'
group by cls.class_name
order by count(*) desc

/* answer (at the time of writing) = 
Osmotic Laxative */

select floor(4000 / cast(strength_numerator_value as float)) as num_tablets
from intermediate.int_rxnorm_clinical_products_to_ingredient_strengths cpstr
where clinical_product_rxcui = '857005'
	and ingredient_component_name = 'acetaminophen'
	and strength_numerator_unit = 'MG'

/* answer = 12 */